Magnetic recording head including background magnetic field generator

ABSTRACT

A perpendicular recording head ( 10 ) for use with magnetic recording media ( 30 ) includes a main pole ( 14 ) and a magnetic field source which is positioned sufficiently close to the main pole tip to generate a background magnetic field in the recording media. A conductive magnetizing coil ( 20 ) surrounding the main pole is preferably used as the magnetic field source. The background magnetic field generated by the magnetizing coil effectively reduces the coercivity of the magnetic recording media in the region affected by the background field. The recording head enables writing on high coercivity/high anisotropy magnetic media, thereby achieving extremely high recording densities.

CROSS REFERENCE TO RELATED APPLICATION

This application is a National Stage (371) appl. of PCT/US00/25650,filed Sep. 9, 2000, which claims the benefit of U.S. Provisional PatentApplication No. 60/154,880, filed Sep. 20, 1999.

FIELD OF THE INVENTION

The present invention relates to recording heads for use with magneticstorage media, and more particularly relates to a perpendicularrecording head which generates a background magnetic field in themagnetic media.

BACKGROUND INFORMATION

Perpendicular magnetic recording heads have been developed for use inhard disk drive systems. Some examples of perpendicular recording headsare described in U.S. Pat. No. 4,438,471 to Ashiki et al., U.S. Pat. No.4,541,026 to Bonin et al., U.S. Pat. No. 4,546,398 to Toda et al., U.S.Pat. No. 4,575,777 to Hosokawa, U.S. Pat. No. 4,613,918 to Kanai et al.,U.S. Pat. No. 4,649,449 to Sawada et al., U.S. Pat. No. 4,731,157 toLazzari, U.S. Pat. No. 4,974,110 to Kanamine et al., and U.S. Pat. No.5,738,927 to Nakamura et al.

In order to increase the data storage density of hard disk drives, theuse of magnetic media having increased magnetic anisotropy has beenproposed. However, highly anisotropic media exhibit extremely highcoercivities, e.g., well over 5,000 Oe. Conventional perpendicularmagnetic recording heads are not capable of recording on media havingsuch high coercivities.

The present invention has been developed in view of the foregoing, andto address other deficiencies of the prior art.

SUMMARY OF THE INVENTION

The present invention provides a magnetic recording head for use withmagnetic recording media having a magnetic field generating coilconfigured and positioned to generate a background magnetic field in themagnetic recording media.

The magnetic recording head preferably comprises a perpendicularconfiguration. In accordance with the present invention, theperpendicular recording head generates a supplemental magnetic fieldwhich increases the magnetic recording field in comparison withconventional perpendicular recording heads. Although not limited to suchuse, perpendicular recording heads of the present invention areparticularly useful for computer hard disk drives.

A typical perpendicular recording head includes a main pole, an opposingpole magnetically coupled to the main pole, and an electricallyconductive magnetizing coil surrounding the main pole. The bottom of theopposing pole will typically have a surface area greatly exceeding thesurface area of the tip of the main pole. In a preferred embodiment,electrical current flowing through the magnetizing coil creates a fluxthrough the main pole tip and also generates the background magneticfield in the recording media.

A typical magnetic recording medium for use in conjunction with thepresent perpendicular recording head includes an upper layer havingmultiple magnetically permeable tracks separated by nonmagnetictransitions, and a magnetically permeable lower level. The lower levelis magnetically soft relative to the tracks.

To write to the magnetic recording medium, the recording head isseparated from the magnetic recording medium by a distance known as theflying height. The magnetic recording medium is moved past the recordinghead so that the recording head follows the tracks of the magneticrecording medium, with the magnetic recording medium first passing underthe opposing pole and then passing under the main pole. Current ispassed through the coil to create magnetic flux within the main pole.The magnetic flux will pass from the main pole tip through the track,into the lower layer, and across to the opposing pole. In addition tothe magnetic field generated at the main pole tip, a supplementalmagnetic field is generated in accordance with the present invention.The combined magnetic flux from the pole tip and from the coil causesthe magnetic fields in the tracks to align with the magnetic flux of therecording head. Changing the direction of electric current changes thedirection of the flux created by the recording head and therefore themagnetic fields within the magnetic recording medium.

An aspect of the present invention is to provide a perpendicularrecording head including a main pole having a tip, and an electricallyconductive magnetizing coil positioned sufficiently close the main poletip to generate a background magnetic field in the magnetic recordingmedium when current is passed through the magnetizing coil.

Another aspect of the present invention is to provide a magneticrecording apparatus comprising a magnetic recording medium and arecording head. The magnetic recording medium includes an upper layerhaving a plurality of data storage tracks, and a lower layer beingmagnetically soft relative to the data storage tracks. The recordinghead includes a main pole having a tip, and an electrically conductivemagnetizing coil positioned sufficiently close the main pole tip togenerate a background magnetic field in the magnetic recording mediumwhen the recording head is positioned at a flying height above themagnetic recording medium and current is passed through the magnetizingcoil.

A further aspect of the present invention is to provide a method ofstoring data on a magnetic storage medium. The method includes the stepsof providing a magnetically permeable main pole, providing a magneticstorage medium adjacent the main pole, directing magnetic flux from themain pole toward the magnetic storage medium, and additionallygenerating a background magnetic field in the magnetic storage medium.

These and other aspects of the present invention will be more apparentfrom the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of magnetic field strength versus distance from theair bearing surface of a conventional perpendicular recording head,illustrating a substantial drop-off in magnetic field strength as thedistance is increased.

FIG. 2 is a partially schematic side sectional view of a perpendicularrecording head including a background magnetic field-generating coil inaccordance with an embodiment of the present invention.

FIG. 3 is an enlarged view of a portion of the recording head of FIG. 2.

FIG. 4 is a partially schematic side sectional view of a perpendicularrecording bead pole tip and magnetic coil configuration in accordancewith an embodiment of the present invention.

FIG. 5 is a partially schematic side sectional view of a perpendicularrecording head pole tip and magnetic coil configuration in accordancewith another embodiment of the present invention.

FIG. 6 is a graph comparing magnetic flux density of a perpendicularrecording head with and without the generation of a background magneticfield.

FIG. 7 is partially schematic side sectional view of a test apparatusfor generating a background magnetic field in accordance with thepresent invention.

FIG. 8 is a graph of playback level versus time, showing theeffectiveness of the test apparatus illustrated in FIG. 7.

DETAILED DESCRIPTION

The preferred embodiment of the present invention provides aperpendicular recording head for use with magnetic recording media. Asused herein, “recording head” means a head adapted for read and/or writeoperations.

The present invention has been developed in order to overcome certainproblems with conventional hard disk drive systems. Granular magneticrecording media used in such systems is subject to superparamagneticinstabilities when the anisotropy energy of the grains (K_(u)×V, where Vis the grain volume) becomes comparable to the energy of thermalfluctuations, kT. Improvements in recording densities requirescontinuous refinement of the grain size. Higher anisotropy materials aredesirable in order to keep the media thermally stable. As an example,the L10 phase of Co₅₀Pt₅₀ has an anisotropy energy K_(u)=4×10⁶ J/m³(compare with K_(u)=˜10⁵ J/m³ for CoCr media). Such high anisotropyreduces the critical size at which grains become thermally unstable toless than 1 nm. Utilizing these materials for recording media canpotentially extend the recording densities well beyond 100 Gbit/in².However, a major obstacle preventing utilization of high anisotropymedia is that such media exhibit exceptionally high coercivities, e.g.,in excess of 5,000 Oe.

The magnitude of the fields generated by conventional perpendicularrecording heads is limited by the saturation moment of the yokematerial. FIG. 1 is a graph illustrating the dependence of magnet fieldstrength on the distance from the pole tip or air-bearing surface (ABS)for a conventional single-pole perpendicular head utilizing FeAlN(saturation moment of 2Tesla) as the pole material. At distances greaterthan 15 nm from the ABS, the field drops below 5,000 Oe. Thisarrangement is therefore not sufficient for recording on media withcoercivities of 5,000 Oe and higher.

FIG. 2 schematically illustrates a single pole perpendicular recordinghead 10 in accordance with an embodiment of the present invention. Theperpendicular recording head 10 includes a yoke 12 made of magneticallypermeable material such as NiFe, CoZrNb, CoZrTa, CoNiFe, FaAlN, FeTaN,CoFe, CoFeB or any other soft magnetic materials, including multiplelayers or laminates of such materials. A main pole 14 extends from theyoke 12 and includes a main pole tip 16. The main pole 14 may be made ofany suitable magnetically permeable material such as NiFe, FeAlN, FeTaN,CoFe, CoFeB, CoFeN or any other soft magnetic materials, includingmultiple layers of such materials. An opposing pole 18 is magneticallycoupled to the main pole 14. In accordance with the present invention,an electrically conductive magnetizing coil 20 surrounds the yoke 12 andmain pole 14. As shown in FIG. 2, the magnetizing coil 20 is locatedclose to the main pole tip 16. Electrical current is supplied to thecoil 20 through electrical connections 22. The magnetizing coil 20 maybe made of any suitable electrically conductive material, such as Cu,Ag, Au or any other high conductivity materials or alloys.

As shown in FIG. 2, the perpendicular recording head 10 is positionedabove a magnetic storage media including a hard magnetic recording layer30 and a soft magnetic underlayer 32. A protective overcoat 33 such asdiamond-like carbon is applied over the recording layer 30. Duringrecording operations, the magnetic media moves in the direction of thearrow shown in FIG. 2.

The recording layer 30 may be made of any suitable hard magneticmaterial such as CoCrPt, CoCrPtTa, CoCrPtB, CoCrPtTaNb or other highanisotropy hexagonal Co-containing alloys. The recording layer 30 mayalso be made of CoPt, FePt, CoPd, FePd or other high anisotropy L10materials. High anisotropy materials such as Co/Pd, CoB/Pd, CoCr/Pd,CoCrPt/Pd, CoCrPd/Pt, CoB/Pt, Co/Pt, CoCr/Pt, Fe/Pd and Fe/Pt may alsobe used as the recording layer 30. Furthermore, high anisotropy ferritessuch as Ba ferrite may be used as the recording layer 30. Preferredmaterials for the recording layer 30 include L10 materials such as CoPt,FePt, CoPd and FePd, and multilayers of Co/Pt and Co/Pd. The recordinglayer may have a relatively high anisotropy energy K_(u), e.g., greaterthan about 10⁶ J/m³. For example, recording layers having anisotropyenergy K_(u) levels of from about 10⁶ to about 10⁸ μm³ may be used. Therecording layer may also have a relatively high coercivity above 5,000Oe, e.g., above 8,000 or 10,000 Oe. The underlayer 32 may be made of anysuitable soft magnetic material, such as FeAlN, FeTaN, CoFe, CoFeB,CoFeN or other high moment soft magnetic materials or soft magneticfilms comprising multiple layers of such materials.

FIG. 3 is an enlarged view of a portion of the perpendicular recordinghead 10 of FIG. 2, showing dimensional details of the yoke 12, main pole14 and magnetizing coil 20. The magnetizing coil 20 has a radialdimension R measured from the center of the yoke 12 or the longitudinalaxis of the main pole 14. The coil 20 is located at a distance D fromthe main pole tip 16, measured in a direction parallel with thelongitudinal axis of the main pole 14 (normal to the surface of therecording layer 30). The main pole tip 16 is located at a flying heightH above the upper surface of the protective layer 33. The main pole tip16 preferably forms part of the air bearing surface of the recordinghead 10. The magnetizing coil 20 is positioned at a distance Z from theupper surface of the recording layer 30, measured in a directionparallel with the longitudinal axis of the main pole 14. The distance Zis equal to the sum of the distances D and H, plus the thickness of theprotective layer 33. As further shown in FIG. 3, the yoke 12 has athickness T_(y) which is preferably larger than the thickness T_(p) ofthe main pole 14.

The dimensions R, D, H, Z, T_(y) and T_(p) are preferably selected inaccordance with the present invention to produce a sufficient backgroundmagnetic field in the recording layer 30 when current flows through thecoil 20. For many perpendicular recording head configurations, Rpreferably ranges from about 0.1 to about 5 micron, D ranges from about0.1 to about 5 micron, H ranges from zero to about 0.1 micron, and Zranges from about 0.1 to about 5 micron. The yoke thickness T_(y) maytypically be from about 0.1 to about 5 micron, preferably from about 0.1to about 1 micron. The main pole thickness T_(p) may be from about 0.01to about 0.5 micron, preferably from about 0.01 to about 0.1 micron.

In accordance with the present invention, the ratio of the coil radialdimension R to the distance D is preferably controlled in order togenerate the desired background magnetic field in the recording layer30, as more fully described below. The ratio of R:D typically rangesfrom about 1:1 to about 10:1, preferably from about 1:1 to about 5:1.The ratio of the yoke thickness T_(y) to the pole thickness T_(p) isalso controlled. The ratio of T_(y):T_(p) preferably ranges from about1:1 to about 10:1. More preferably, the ratio of T_(y):T_(p) ranges fromabout 2:1 to about 5:1.

Although the magnetizing coil 20 shown in FIGS. 2 and 3 comprises asingle circular winding, multiple windings and/or other coil shapes maybe used. For example, the coil 20 may alternatively be square,rectangular, helical, straight, etc. Similarly, the cross-sectionalshapes of the yoke 12 and main pole 14 may be round, square,rectangular, or the like. The magnetizing coil 20 preferably surroundsthe yoke 12 and main pole 14 as shown in FIGS. 2 and 3. However, thecoil could be located at a different position on the head 10 as long asa sufficient background magnetic field is generated. Furthermore,although not preferred, a permanent magnet could be used in place of, orin addition to, the coil 20.

FIGS. 4 and 5 schematically illustrate alternative coil configurationsin accordance with the present invention. In the embodiment shown inFIG. 4, an electrically conductive magnetizing coil 24 surrounds and ispositioned directly adjacent the outer surface of the yoke 12. In theembodiment shown in FIG. 5, an electrically conductive magnetizing coil26 surrounds and is embedded in a recess 28 which extends around theouter surface of the yoke 12. In FIGS. 4 and 5, each of the magnetizingcoils 24 and 26 is shown as a single winding around the yoke 12.Alternatively, multiple coil windings may be used. Although themagnetizing coils 24 and 26 shown in FIGS. 4 and 5 have square crosssections, any other suitable sectional shape may be used, such asrectangular, circular, etc. The cross-sectional thickness of themagnetizing coils 20, 24 and 26 typically ranges from about 0.01 toabout 5 micron, preferably from about 0.1 to 2 micron.

In the embodiments shown in FIGS. 2-5, the pole tip 16 comprises a flatsurface. Alternatively, the present design can be combined with aperpendicular head having a concave pole tip design, such as the concavepole tips described in U.S. patent application Ser. No. 09/665,598,filed Sep. 19, 2000 entitled Perpendicular Recording Head IncludingConcave Tip, which is incorporated herein by reference.

In accordance with the present invention, the amount of electricalcurrent supplied to the magnetizing coil 20 is controlled in order togenerate the desired background magnetic field strength at the recordinglayer 30, the background magnetic field is typically greater than 100Gauss, preferably greater than 1,000 or 2,000 Gauss. Depending upon themagnetic properties of the recording layer 30, the background magneticfield may typically range from about 100 to about 20,000 Gauss,preferably from about 1,000 to about 15,000 Gauss, and more preferablyfrom about 5,000 to about 10,000 Gauss at the recording layer 30. Thebackground magnetic field effectively decreases the coercivity of therecording layer 30. The coercivity of the recording layer 30 may bedefined as H_(c), and the background magnetic field effectivelydecreases the coercivity H_(c) to a lower value defined as H_(b). Theratio of H_(b):H_(c) preferably ranges from about 1:10 to about 9:10,more preferably from about 3:10 to about 8:10. In a particularlypreferred embodiment, the ratio of H_(b):H_(c) is about 5:10.

In accordance with a further aspect of the present invention, the levelof the background magnetic field H_(b) is controlled in relation to thestrength of the magnetic field H_(p) generated at the main pole tip 16.Preferably, the ratio of H_(b):H_(p) is from about 1:10 to about 10:1,more preferably from about 4:10 to about 3:1. As a particular example, arecording layer having a coercivity of 10,000 Oe may be written on witha recording head of the present invention which generates a pole tipcoercivity H_(p) of 5,000 Oe and a background coercivity H_(b) of 8,000Oe. Thus, while the magnetic flux generated from the pole tip would notbe sufficient to write on the recording layer alone, the backgroundmagnetic field is sufficient to effectively reduce the dynamiccoercivity of the recording layer, thereby enabling writing on therecording layer.

As long as the pole tip is not completely saturated, the magnetic fluxis mainly concentrated within the pole tip. A standard way of operatinga single pole head is to choose a current value SAT that causes completesaturation of the pole tip. The fields generated by the saturated poleare localized and their gradients within the recording layer determinethe minimum bit cell size. If the current in the coil is furtherincreased by ΔI (ΔI=I-I_(SAT)), the extra flux generated will no longerbe confined to the pole tip. The magnitude of the additional field ABwill be proportional to ΔI. The field flux will be spread over asignificantly larger region within the recording layer, the size ofwhich is determined by the diameter of the coil due to the relativeproximity of the coil to the recording layer. The magnitude of ΔB can befine-tuned by the current in the coil. For a single turn coil themagnitude of ΔB is given by:${{\Delta\quad B} = {\frac{\mu_{0}\Delta\quad I}{2}\frac{R^{2}}{\left( {R^{2} + z^{2}} \right)^{3/2}}}},$where R is the radius of the coil and z is the distance from the coil tothe hard layer. For R=0.2 μm and z=0.1 μm, background fields in excessof 1Tesla (10,000 Oe) can be generated with currents as small as 400 mAwith a resolution of about 25 Oe/mA if a single turn coil is used.

The presence of the additional background field AB effectively reducescoercivity of the recording layer. It enables writing on high coercivitymedia using heads based on available soft materials. Because of highdata rates, the dynamic coercivity will be affected by the introductionof such background field because the dynamic coercivity is significantlyhigher than the static coercivity.

FIG. 6 illustrates magnetic field simulation results using a boundaryelement solver, Amperes, for different values of coil current. The fieldprofiles at I=50 mA (=I_(SAT)) and I=200 mA (ΔI=150 mA) are given. Theadditional 150 mA of current on top of the saturation current I_(SAT)generates a background field of 4,000 Oe. This background field wouldnot be high enough to erase the previously recorded bit pattern, but iteffectively increases the write field of the pole tip, i.e., decreasesthe effective media coercivity.

A test was conducted to confirm the performance of the present design.FIG. 7 schematically illustrates the test. A conventional perpendicularwriter 34 having a magnetic coil 35 placed far from the pole tip 36 orthe air bearing surface of the writer was used in combination with anexternal field source 38 (a strong rare earth-based permanent magnetthat could generate stray fields in excess of 2,000 Oe) to simulate abackground field from a coil if the coil was placed in close proximityto the ABS. The recording tests were conducted on a multilayerperpendicular media 30 comprised of twenty layers of Co/Pd on a softunderlayer of FeAlN, having a coercivity in excess of 8,000 Oe. First,the media was DC saturated (DC erased) in a strong magnetic fieldgenerated using a large electromagnet. As expected, due to demagnetizingfields, no stray field emanates from the DC saturated media, resultingin zero signal read-out. Next, recording with a conventionalperpendicular writer was attempted, which failed due to insufficientmagnitude of the recording field. The recording failure was confirmed bythe absence of the read-out signal. Finally, a small permanent magnetwas placed above the recording head in close proximity to the media, asschematically illustrated in FIG. 7, and another recording attempt wasperformed. The result was a well-recorded bit pattern with the playbackshown in FIG. 8. The results shown in FIG. 8 demonstrate that theanisotropy of the recording media is effectively temporarily lowered bythe application of the background magnetic field.

The present recording system effectively reduces the coercivity of themedia. This is accomplished by generating a background field utilizing amagnetizing coil which is placed in proximity to the recording layer.This recording system enables writing on high coercivity/high anisotropymedia that can support very high recording densities, e.g., in excess of100 Gbit/in². High recording densities can therefore be achieved withoutthe necessity of major changes in the recording process.

Whereas particular embodiments of this invention have been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims.

1. A perpendicular recording head for use with a magnetic recording medium, the perpendicular recording head comprising: a main pole having a tip; a yoke connected to the main pole having a thickness greater than a thickness of the main pole; and an electrically conductive magnetizing coil at least partially surrounding the yoke and positioned sufficiently close to the main pole tip to generate a background magnetic field in the magnetic recording medium when current is passed through the magnetizing coil, wherein the current passed through the magnetizing coil is sufficient to cause magnetic saturation of the main pole tip, and the combination of a magnetic field generated from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium.
 2. The perpendicular recording head of claim 1, wherein the magnetizing coil at least partially surrounds the main pole.
 3. The perpendicular recording head of claim 2, wherein the magnetizing coil comprises a single winding around the main pole.
 4. The perpendicular recording head of claim 1, wherein the magnetizing coil is spaced apart from an outer surface of the yoke.
 5. The perpendicular recording head of claim 1, wherein the magnetizing coil is positioned directly adjacent an outer surface of the yoke.
 6. The perpendicular recording head of claim 1, wherein the magnetizing coil is at least partially embedded in an outer surface of the yoke.
 7. The perpendicular recording head of claim 1, wherein the ratio of the yoke thickness to the main pole thickness is less than about 10:1.
 8. The perpendicular recording head of claim 1, wherein the ratio of the yoke thickness to the main pole thickness is from about 2:1 to about 5:1.
 9. The perpendicular recording head of claim 2, wherein the magnetizing coil has a radial dimension R measured from an axis defined by the main pole, the magnetizing coil has a pole tip distance D measured from the magnetizing coil to the pole tip in a direction parallel with the main pole axis, and the ratio of R:D is from about 1:1 to about 10:1.
 10. The perpendicular recording head of claim 9, wherein the ratio of R:D is from about 1:1 to about 10:1.
 11. The perpendicular recording head of claim 9, wherein the radial dimension R is from about 0.1 to about 5 micron.
 12. The perpendicular recording head of claim 9, wherein the pole tip distance D is from about 0.1 to about 5 micron.
 13. The perpendicular recording head of claim 1, wherein the background magnetic field is greater than 100 Gauss.
 14. The perpendicular recording head of claim 1, wherein the background magnetic field is greater than 1,000 Gauss.
 15. The perpendicular recording head of claim 1, wherein the background magnetic field is greater than 2,000 Gauss.
 16. The perpendicular recording head of claim 1, wherein the background magnetic field is from about 5,000 to about 10,000 Gauss.
 17. The perpendicular recording head of claim 1, wherein the background magnetic field has a strength H_(b), a magnetic field generated at the main pole tip has a strength H_(p), and the ratio of H_(b):H_(p) is from about 1:10 to about 10:1.
 18. The perpendicular recording head of claim 17, wherein the ratio of H_(b):H_(p) is from about 4:10 to about 3:1.
 19. A magnetic recording apparatus, comprising: a magnetic recording medium including an upper layer having a plurality of data storage tracks, and a lower layer being magnetically soft relative to the data storage tracks; and a recording head including a main pole having a tip, a yoke connected to the main pole having a thickness greater than a thickness of the main pole, and an electrically conductive magnetizing coil at least partially surrounding the yoke and positioned sufficiently close the main pole tip to generate a background magnetic field in the magnetic recording medium when the recording head is positioned at a flying height above the magnetic recording medium and current is passed through the magnetizing coil, wherein the current passed through the magnetizing coil is sufficient to cause magnetic saturation of the main pole tip, and the combination of a magnetic field generated from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium.
 20. The magnetic recording apparatus of claim 19, wherein the magnetizing coil at least partially surrounds the main pole.
 21. The magnetic recording apparatus of claim 20, wherein the magnetizing coil has a radial dimension R measured from an axis defined by the main pole, the magnetizing coil has a pole tip distance D measured from the magnetizing coil to the pole tip in a direction parallel with the main pole axis, and the ratio of R:D is from about 1:1 to about 10:1.
 22. The magnetic recording apparatus of claim 20, wherein the background magnetic field has a strength H_(b), a magnetic field generated at the main pole tip has a strength H_(p), and the ratio of H_(b):H_(p) is from about 1:10 to about 10:1.
 23. The magnetic recording apparatus of claim 19, wherein the magnetizing coil generates a magnetic field at the main pole tip in addition to the background magnetic field that is generated when the current is passed through the magnetizing coil.
 24. A method of storing data on a magnetic storage medium, the method comprising the steps of: providing a magnetically permeable main pole having a tip; providing a yoke connected to the main pole having a thickness greater than a thickness of the main pole; providing an electrically conductive magnetizing coil at least partially surrounding the yoke adjacent to the main pole tip; providing a magnetic storage medium adjacent the main pole tip; passing current through the magnetizing coil sufficient to cause magnetic saturation of the main pole tip; directing a magnetic field from the saturated main pole tip toward the magnetic storage medium; and additionally generating a background magnetic field in the magnetic storage medium from the magnetizing coil, wherein the combination of the magnetic field from the saturated main pole tip and the background magnetic field is sufficient to write on the magnetic recording medium. 